This application relates to the merging and mixing of individual drops of fluid, both in small numbers and in arrays. More specifically, the application provides apparatuses, methods and systems for placing drops on a surface and moving, merging and mixing the drops of fluid across the surface through use of electrostatic actuation, magnetic actuation or other mechanisms.
Mixing of fluid by use of magnetic mixers is a known process. Research in this area has included the use of MEMS technology to demonstrate enhanced micro-scale mixing (see, Lu, Ryu and Liu in Journal of Microelectromechanical Systems, Vol. 11, No. 5, October 2002, pp. 462-469; “Micromixers—a review on passive and active mixing principles” by V. Hessel et al, Chemical Engineering Science 60 (2005), pp. 2479-2501).
Additionally, research related to the use of magnetic particles and external fields to enhance mixing of biological reagents has been reported (see, “Magnetically Driven Mixing within a Microarray Geometry using Functionalized Magnetic Nanoparticles”, by S. Agarwal and P. Laibinis, The 80th ACS Colloid and Surface Science Symposium (Jun. 18-21, 2006); “A Magnetic Force Driven Chaotic Micro-Mixer”, by H. Suzuki and C. Ho, Proceedings Int. Conf. MEMS '02. (2002), Las Vegas, USA, pp. 40-43; and “Overcoming the Diffusion Barrier: Ultra-fast Micro-scale Mixing via Ferrofluids”, by L. Mao and H. Koser, Proceedings IEEE Transducers '07 (2007), Lyon, France, pp. 1829-1832).
Another example of using magnetic particles to enhance mixing in moving fluids has been described in U.S. Pat. No. 3,995,835, titled, Magnetic mixer.
However, the literature has not revealed an apparatus, method or system appropriate for the uses addressed in this application.